package es.juanc.net.tftp;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.SocketException;
import java.net.UnknownHostException;

import org.apache.commons.net.tftp.TFTP;
import org.apache.commons.net.tftp.TFTPClient;

/***
 * This is an example of a simple Java tftp client using NetComponents.
 * Notice how all of the code is really just argument processing and
 * error handling.
 * <p>
 * Usage: tftp [options] hostname localfile remotefile
 * hostname   - The name of the remote host
 * localfile  - The name of the local file to send or the name to use for
 *              the received file
 * remotefile - The name of the remote file to receive or the name for
 *              the remote server to use to name the local file being sent.
 * options: (The default is to assume -r -b)
 *        -s Send a local file
 *        -r Receive a remote file
 *        -a Use ASCII transfer mode
 *        -b Use binary transfer mode
 * <p>
 ***/
public class TFTPTest {

	static final String USAGE = "Usage: tftp [options] hostname localfile remotefile\n\n"
			+ "hostname   - The name of the remote host\n"
			+ "localfile  - The name of the local file to send or the name to use for\n"
			+ "\tthe received file\n"
			+ "remotefile - The name of the remote file to receive or the name for\n"
			+ "\tthe remote server to use to name the local file being sent.\n\n"
			+ "options: (The default is to assume -r -b)\n"
			+ "\t-s Send a local file\n"
			+ "\t-r Receive a remote file\n"
			+ "\t-a Use ASCII transfer mode\n"
			+ "\t-b Use binary transfer mode\n";

	public final static void main(String[] args) {
		
		boolean receiveFile = true, closed;
		int transferMode = TFTP.BINARY_MODE, argc;
		String arg, hostname, localFilename, remoteFilename;
		TFTPClient tftp;

		// Parse options
		for (argc = 0; argc < args.length; argc++) {
			arg = args[argc];
			if (arg.startsWith("-")) {
				if (arg.equals("-r"))
					receiveFile = true;
				else if (arg.equals("-s"))
					receiveFile = false;
				else if (arg.equals("-a"))
					transferMode = TFTP.ASCII_MODE;
				else if (arg.equals("-b"))
					transferMode = TFTP.BINARY_MODE;
				else {
					System.err.println("Error: unrecognized option.");
					System.err.print(USAGE);
					System.exit(1);
				}
			} else
				break;
		}

		// Make sure there are enough arguments
		if (args.length - argc != 3) {
			System.err.println("Error: invalid number of arguments.");
			System.err.print(USAGE);
			System.exit(1);
		}

		// Get host and file arguments
		hostname = args[argc];
		localFilename = args[argc + 1];
		remoteFilename = args[argc + 2];

		// Create our TFTP instance to handle the file transfer.
		tftp = new TFTPClient();

		// We want to timeout if a response takes longer than 60 seconds
		tftp.setDefaultTimeout(60000);

		// Open local socket
		try {
			tftp.open();
		} catch (SocketException e) {
			System.err.println("Error: could not open local UDP socket.");
			System.err.println(e.getMessage());
			System.exit(1);
		}

		// We haven't closed the local file yet.
		closed = false;

		// If we're receiving a file, receive, otherwise send.
		if (receiveFile) {
			FileOutputStream output = null;
			File file;

			file = new File(localFilename);

			// If file exists, don't overwrite it.
			if (file.exists()) {
				System.err.println("Error: " + localFilename
						+ " already exists.");
				System.exit(1);
			}

			// Try to open local file for writing
			try {
				output = new FileOutputStream(file);
			} catch (IOException e) {
				tftp.close();
				System.err
						.println("Error: could not open local file for writing.");
				System.err.println(e.getMessage());
				System.exit(1);
			}

			// Try to receive remote file via TFTP
			try {
				tftp
						.receiveFile(remoteFilename, transferMode, output,
								hostname);
			} catch (UnknownHostException e) {
				System.err.println("Error: could not resolve hostname.");
				System.err.println(e.getMessage());
				System.exit(1);
			} catch (IOException e) {
				System.err
						.println("Error: I/O exception occurred while receiving file.");
				System.err.println(e.getMessage());
				System.exit(1);
			} finally {
				// Close local socket and output file
				tftp.close();
				try {
					output.close();
					closed = true;
				} catch (IOException e) {
					closed = false;
					System.err.println("Error: error closing file.");
					System.err.println(e.getMessage());
				}
			}

			if (!closed)
				System.exit(1);

		} else {
			// We're sending a file
			FileInputStream input = null;

			// Try to open local file for reading
			try {
				input = new FileInputStream(localFilename);
			} catch (IOException e) {
				tftp.close();
				System.err
						.println("Error: could not open local file for reading.");
				System.err.println(e.getMessage());
				System.exit(1);
			}

			// Try to send local file via TFTP
			try {
				tftp.sendFile(remoteFilename, transferMode, input, hostname);
			} catch (UnknownHostException e) {
				System.err.println("Error: could not resolve hostname.");
				System.err.println(e.getMessage());
				System.exit(1);
			} catch (IOException e) {
				System.err
						.println("Error: I/O exception occurred while sending file.");
				System.err.println(e.getMessage());
				System.exit(1);
			} finally {
				// Close local socket and input file
				tftp.close();
				try {
					input.close();
					closed = true;
				} catch (IOException e) {
					closed = false;
					System.err.println("Error: error closing file.");
					System.err.println(e.getMessage());
				}
			}

			if (!closed)
				System.exit(1);

		}

	}

}
